Permanent magnet holding devices



Dec. 31, 1968 M. BAERMANN 3,419,832

PERMANENT MAGNET HOLDING DEVICES Filed Sept. 28, 1966 Fig.2

mvsw-ron /MX MAM/{IAN United States Patent 3 419 832 PERMANENT MAGNE'lHOLDING DEVICES Max Baermann, 506 Bensberg-Wulfshof, Bezirk Cologne,

Germany Filed Sept. 28, 1966, Ser. No. 582,665 Claims priority,application (ifrmany, Oct. 2, 1965, B 63 63 1 Claim. 01. 335-285)ABSTRACT OF THE DISCLOSURE This invention relates to permanent magnetholding devices of bar shape for holding magnetically adhesive objectssuch as tools, working devices and the like, made of iron or steel.

Permanent magnetic holding bars are known in various constructions. Oneof the known 'holding bars consists of an elongated rectangular supportprovided with spacers and covered with a plate of isotropic oranisotropic permanent magnet rubber. The permanent magnet rubber plateis magnetized in the longitudinal direction with striptype poles.

Holding bars of such construction cannot provide high specificattractive powers so that they cannot be used for relatively heavyobjects with a small adhesive surface. In order to increase the specificattractive power or holding force, it has already been proposed toprovide such magnets with iron pole plates on their pole surfaces, whichplates collect the lines of magnetic force and concentrate them on theholding surface.

Such holding systems, however, have no large longitudinal extension. Ifit is desired to produce holding bars having a relatively largelongitudinal extension, this involves high costs for iron pole shoes andpermanent magnet material because several such systems formed bypermanent magnets and iron pole plates must be combined to form a bar.Due to these high costs, holding bars of this type are relativelyexpensive.

The present invention aims at obviating the foregoing disadvantages byproviding a permanently magnetic holding bar having a simple design,which although possessing a high attractive power, presents only lowproduction costs and can easily be made of any length necessary for thedesired holding purposes.

To this end, the present invention consists in a permanent magnetholding device, particularly for holding tools, working devices andsimilar objects made of iron or steel which comprises at least twoelongated U-shaped members of ferro magnetic material arranged oneinside the other in spaced relationship, an elongated permanent magnetpositioned between such bars or channels so that the one surface of suchmagnet having a north pole adheres to one of said bars or channels andthe other surface of such magnet having a south pole adheres to theother of said bars or channels, the lengths of the legs of the U- shapedmembers being so dimensioned that their ends are situated in the sameplane.

By virtue of this construction, it is possible to produce a permanentmagnet holding bar of great length from which smaller lengths can beobtained by simply cutting the bar into desired lengths.

By using U-shaped members and by their particular arrangement withregard to the permanent magnet, the lines of magnetic force are guidedto the ends of the legs of the bars and are strongly concentrated thereso that in 3,419,832 Patented Dec. 31, 1968 spite of the simple design ahigh magentic attractive power is available.

Furthermore, the construction according to the invention renders it alsopossible to use a cheap permanent magnet material of relatively lowremanence. Preferably, a flexible permanent magnet material, so-calledmagnetic rubber, is used which is composed of a mixture of a highlycoercive powdered permanent magnet material such as Barium Ferrite and aflexible plastic binder, the binder being cured after the mixing so thatit holds the particles of magnet material together.

Preferably, the permanent magnet is fastened between the U-shapedmembers by means of rivets. Alternatively, the magnet may be fastened tothe U-shaped members by means of a suitable adhesive. The remainingspace between the U-shaped members may be filled with any suitablefilling material, such as a plastics material, cast resin, or the like.

The princiapl object of the invention is the provision of a novelpermanent magnet holding device which has improved holding power andwhich may be cheaply manufactured.

Still another object of the invention, the provision of a novel improvedmagnet holding device which is made up of a pair of U-shaped membersarranged one inside the other with a permanent magnet therebetween andhaving the ends of the legs thereof in a plane which will form a holdingsurface for ferro magnetic articles such as tools, working devices, andthe like.

Still another object of the invention, the provision of a novelpermanent magnet holding device which, in effect, has a plurality ofpermanent magnet holding surfaces.

In order that the invention may be more readily understood, reference ismade to the accompanying drawings which illustrate diagrammatically and,by way of example, one embodiment thereof and in which:

FIG. 1 is a perspective view of the permanently magnetic holding bar;and

FIG. 2 is a section of theholding bar fastened to a wall with a toolheld on it.

Referring now to the drawings wherein the showings are for the purposesof illustrating preferred embodiments of the invention only and not forthe purposes of limiting same, FIG. 1 shows a permanent magnet holdingdevice comprised of a pair of U-shaped members 1, 4 arranged with theirbases and legs 3, 5 respectively and spaced from each other. Anelongated permanent magnet 2 is positioned between the members,preferably between the bases of the two members 1, 4. The two memberswith the permanent magnet therebetween are fastened together by anysuitable means but in the embodiment shown in the figures by means oftubular rivets 6.

The members 1, 4 are of a term magnetic material such as iron or steel,and their legs 3 and 5, taken in conjunction with the thickness of thepermanent magnet 2, have a length such that the ends all lie in the sameplane and form a holding surface for ferro magnetic objects to be held.

The permanent magnet 2 in the preferred embodiment is generallyrectangular in cross-sectional shape and has an axis of magnetizationperpendicular to and through the surfaces adjacent the bases of theU-shaped members 1, 4. While the poles N and S are shown only along thecenterline of the surfaces, it will be understood that the entiresurface of the permanent magnet 2 adjacent the bases of the U-shapedmembers 1, 4 exhibits a similar magnetic polarity.

The permanent magnet 2 may be made in any desired way but in thepreferred embodiment is comprised of a mixture of Barium Ferrite and aflexible plastic binder. The binder is cured after the mixing so that it'holds the particles of the magnet material together. The permanentmagnet 2 may be manufactured as is shown in United States Patent No.2,959,852 with the exception that the magnet poles instead of being onone surface only are on opposite parallel surfaces.

FIG. 2 shows the fastening of the holding bar onto a Wall. The tubularrivets 6 serve not only to connect the U-shaped members and thepermanent magnet 2 in as sembled relationship but also at the same timereceive the fastening screws for mounting the device on a wall. In FIG.2 the permanent magnet 2 substantially fills the space between the twoU-shaped members. If desired, and not shown, the remainder of the spacemay be filled with other non-magnetic material.

FIG. 2 also shows a tool 7 of ferro magnetic material held onto theholding surfaces formed by the ends of the legs 3 and 5.

The permanent magnet 2 is shown as having a width such as to only extendbetween the bases of the members 1, 4. Obviously the entire space or anyportion thereof between the members 1, 4 can be filled with the permanent magnet 2.

Obviously, more than two U-shaped members may be employed, e.g., threeor four, with the ends of their legs in the same plane and with apermanent magnet 2 disposed between adjacent members and so polarizedthat the ends of the legs are of opposite magnetic polarity.

Thus it will be seen that a permanent magnet holding device has beendescribed which accomplishes all the objects of the invention heretoforeset forth and others and provides a magnetic holding device which issimple in construction, economical to manufacture, and which will have amaximum holding power for a minimum amount of magnetic material.

Having thus described my invention, I claim:

1. A permanent magnet holding device comprising a first elongatedgenerally U-shaped ferromagnetic member having two spaced legs withelongated edge portions and an innner surface between said legs, asecond elongated generally U-shaped ferromagnetic member having twospaced legs with elongated edge portions and an outer surface betweensaid leg portions and facing away therefrom, a flexible permanent magnetstrip secure-d between said inner and outer surfaces, said strip havinga thickness sufficient to locate said edge portions in the same plane,said strip being formed from permanently magnetizable particles embeddedwithin and bonded together by aflexible binder and said strip beingpermanently magnetized to have one pole abutting said inner surface andan opposite pole abutting said outer surface.

References Cited UNITED STATES PATENTS 2,959,832 11/1960 Baermann 335303XR 3,304,527 2/1967 Marrs et al 335--285 GEORGE HARRIS, PrimaryExaminer.

U.S. Cl. X.R. 248206

